I. Field of the Invention
This invention pertains to insertion tools for inserting insulated wires into terminal connecting blocks and terminating the electrical conductor at the block. More particularly, this invention pertains to insertion tools which include impactors to assist in termination of the electrical conductor.
II. Description of the Prior Art
Tools for terminating electrical conductors at a terminal block are well known. Additionally, such tools having hammer mechanisms to assist in termination are also well known. An example of the latter is found in U.S. Pat. No. 3,883,316 to Mason dated May 13, 1975. Mason is typical of prior art termination tools with hammer mechanisms in that the hammer mechanism includes a resiliently displaced sear (shown at 34 in Mason) which is carried within the hammer mechanism and moves laterally to the direction of travel of the hammer mechanism. The sear engages a cam surface which urges the sear against its resilient displacement during sliding motion of the termination tip which is slideably secured to the termination tool. After the termination tip has urged the hammer against the resilience of a main spring a predetermined stroke, the sear presents an opening which is aligned with a pin on the termination tip such that the hammer is free to impact the termination tip. In Mason, the termination tip carries a blade having a cutting edge 12 which, upon impact from the hammer mechanism, severs an electrical conductor. A problem associated with such a tool is that due to the need for a laterally moving sear, there are limitations put on the size and mass of the hammer mechanism thereby compromising its effectiveness. Also, the relatively long longitudinal dimension of the hammer mechanism together with a relatively short spring results in the spring generally being cycled repeatedly from near full compression to near full expansion. This repetition can, over time, take its toll on the spring.
U.S. Pat. No. 2,960,864 to Watts dated Nov. 22, 1960 teaches an insertion tool for making electrical connections. Unlike the Mason patent which uses a hammer mechanism with a laterally movable sear, the Watts patent uses an impactor having a first end with a bore sized to receive an impact pin and a longitudinally displaced second end which acts as a lever point. As the impactor is forced against the urging of a spring, the impactor pivots about the longitudinally displaced pivot point until the impactor bore is aligned with the impactor pin. At this point, the spring forces the impactor against the pin.
The impactor of the Watts patent overcomes one of the disadvantages of the Mason patent in that the need for a sear is eliminated. However, the lever movement of the Watts impactor requires the need for a substantial amount of unused space within the tool to accommodate the displacement of the impactor through the lever action. Also, like the Mason patent, the relatively long longitudinal dimension of the lever action impcator results in use of a short high tension spring which is almost fully compressed during its repeated use.
It is intended the present invention will be particularly useful with a terminal block as described in commonly assigned and copending U.S. patent application Ser. No. 658,268, entitled "Electrical Connector Module With Multiple Connector Housings." As illustrated in U.S. Ser. No. 658,268, each insulation displacement terminal includes a seam or slot including wire piercing edges which cut through the insulation as the wire is slid into the slot and a trimming edge radially opposite the seam or slot which cuts the excess length from a wire as it is installed.
U.S. Ser. No. 658,268, now abandoned, also teaches a tool tip to be used to insert a wire in the insulation displacement terminal. Tool tips for inserting wires into such terminals are also shown in commonly assigned and copending U.S. patent application Ser. No. 800,998, now U.S. Pat. No. 4,663,838 which is a continuation-in-part of commonly assigned copending U.S. patent application Ser. No. 789,470, now abandoned. These applications teach a debris ejecting insertion tool tip for engaging a wire to urge the wire into the split cylinder terminal. The insertion tips of these applications include an ejector for ejecting debris (such as spent insulation) from the tool tip. With such a system where the wire terminating blade is located on the split cylinder terminal, the problem of Mason which included wear of the terminating blade is not experienced since a wire to be terminated is exposed to a fresh blade in each instance.
In addition to the desireability of the above system where the termination blade is located on the split cylinder terminal, it is also desireable to provide an improved insertion tool having an enhanced impact mechanism. Such tools must be of a design which permits them to be employed in a rugged environment. Also, it is desireable that such tools have a minimum number of moving elements and provide maximum impact to assist in terminating a wire. Also, the ability to adjust the tension of such tools is also a desireable feature.